1. Technical Field
The present invention relates to a guide plate for a side air bag, and, more particularly, to a guide plate for a side air bag, which prevents a side air bag from being upwardly deployed so as to allow it to be easily deployed in a downward direction, and ensures sequential deployment of a side air bag tube when the side air bag is deployed.
2. Discussion of Related Art
As is generally known in the art, in an air bag for an automotive vehicle, a sensor is provided to sense impact force upon occurrence of a collision or a sudden stop during high speed running. Therefore, as a signal is transmitted from the sensor depending upon the level of a shock to be applied to the human body, gas is supplied into and quickly inflates an air bag tube to protect a driver or a passenger from being injured.
While the air bag may not operate once throughout the life span of a vehicle, it must properly operate upon occurrence of an accident and must not operate when its operation is not required. Therefore, the air bag is a safety device which requires a high degree of operational reliability.
The air bag is usually installed in each of a steering wheel for a driver's seat and an instrument panel for a passenger's seat. Upon occurrence of a collision, the air bag operates by an impact sensor and an electronic control unit (ECU) and cooperates with a safety belt to protect an occupant from being injured.
If a collision occurs, the impact sensor transmits a signal to the ECU, and the ECU determines whether to operate the air bag depending upon the level of a shock. When it is necessary to operate the air bag, an inflator is actuated and an air bag tube is inflated.
The inflator is connected to the air bag tube which is held in a folded state. As the ECU actuates the ignitor of the inflator, an ignition agent ignites, and a gas generator burns to generate gas. As a consequence, a large amount of gas, which is instantaneously generated, is introduced into the air bag tube, and the air bag tube is quickly inflated.
Meanwhile, if a side collision occurs, a roof side rail portion is severely deformed and is significantly intruded into a passenger space to decrease the size of the passenger space, by which an occupant's head injury rating increases. Therefore, recently, a provision is provided to protect an occupant from a side collision.
An air bag module, which is provided on a side of a vehicle, is generally called a side air bag or a curtain air bag and is installed alongside the roof liner of the vehicle.
The side air bag extends alongside a roof beam constituting the roof of the vehicle from a front pillar through a center pillar to a rear pillar. The side air bag operates according to the same principle as the front air bag in a manner such that a side air bag tube can be deployed depending upon the level of a shock when a side impact is applied to a vehicle.
A side air bag assembly comprises a side air bag which is installed inward of a roof side rail, a center pillar trim which is installed below the roof side rail, a head liner which is installed facing the inside space of the vehicle to be bent upon deployment of the side air bag, and a guide unit for guiding the deployment of the side air bag.
Hereafter, the construction of a side air bag will be concretely described with reference to FIG. 1.
Referring to FIG. 1, a conventional side air bag comprises a side air bag 12 which is installed inward of a roof side rail 10, a center pillar trim 13 which is installed below the roof side rail 10, a head liner 14 which is installed facing the inside space of a vehicle to be bent upon deployment of the side air bag 12, and a guide unit 15 for guiding the deployment of the side air bag 12.
The guide unit 15 is arranged below the side air bag 12 and is installed to be secured to inside of the center pillar trim 13. The guide unit 15 is composed of a guide part 16 for guiding the deployment of the side air bag 12, a fastening member 18 which is fastened to inside of the center pillar trim 13, and a connection part 17 which connects the guide part 16 and the fastening member 18 with each other.
In the conventional side air bag, since an inside guide structure is deformed by an external shock, the deployability of the side air bag is degraded. Also, since separate means for restraining the side air bag from being upwardly deployed is not provided, force is spread and it is difficult to bend the head liner so as to deploy the side air bag. Further, since a reinforcing part is not formed on either side of the side air bag, it is difficult to sequentially deploy the side air bag.
Moreover, as the side air bag is not properly guided into the inside space, that is, the passenger space of the vehicle, the side air bag is likely to be deployed inside the center pillar trim. Furthermore, when the side air bag is deployed, because it is likely to interfere with the center pillar trim, it is not easy to sequentially deploy the side air bag.
As a consequence, because a procedure for deploying the side air bag cannot be smoothly implemented, proper operation of the side air bag cannot be ensured, as a result of which the operational reliability of the side air bag is deteriorated.
Another side air bag for protecting a vehicle occupant from a side impact will be described below with reference to FIGS. 2 and 3.
Referring to FIGS. 2 and 3, a side air bag (hereinafter, simply referred to as an “air bag”) 30 is installed inside of between a roof panel (not shown) and a head liner 24 to be deployed into the passenger space of a vehicle.
The air bag 30 installed in this way has an inflator 20 at one end thereof. The inflator 20 is controlled by an ECU (not shown) depending upon the level of a shock upon occurrence of a side collision to inject a large amount of gas under a high pressure into an air bag tube 36.
A plurality of inner panels 26 and reinforcing brackets 28 are placed between the roof panel and the head liner 24. The head liner 24 is installed next to a door trim and a center pillar trim 22. The end of the head liner 24 is formed with an engagement lip 24a which is bent like a step toward the inner panel 26, and the upper end of the center pillar trim 22 is overlapped with the engagement lip 24a. 
The air bag 30 is placed adjacent to the interface between the head liner 24 and the center pillar trim 22 which are installed as described above.
The air bag 30 has a housing 32. One end of the housing 32 is formed with a mounting part 32a which is bolted to the inner panel 26. The air bag tube 36 to be deployed by the inflator 20 is received in the housing 32 in a folded state. The housing 32 has at one side thereof a door 32b to be opened by the air bag tube 36 upon deployment of the air bag tube 36.
When the door 32b is opened by the air bag tube 36 upon deployment of the air bag tube 36, as the three sides of the door 32b are freed from the housing 32, the door 32b is rotated (clockwise when viewed in FIG. 3) and is brought into contact with the upper end of the center pillar trim 22, as a result of which the space between the center pillar trim 22 and the inner panel 26 is closed and the deployment of the air bag 30 is properly guided.
In this way, the air bag tube 36 being deployed is prevented from being introduced into the space between the center pillar trim 22 and the inner panel 26.
A guide plate 34 is installed adjacent to the lower surface of the housing 32 which faces the center pillar trim 22. When the air bag tube 36 is deployed, the guide plate 34 is brought into contact with the inner panel 26 to limit the rotation of the lower wall of the housing 32 and the door 32b. Thus, the guide plate 34 causes the door 32b to be stably held on the upper end of the center pillar trim 22.
In greater detail, when the air bag tube 36 is deployed, the upper end of the door 32b is detached from the housing 32, and the lower wall of the housing 32 is pushed downward to be rotated clockwise. Thereafter, the guide plate 34, which is positioned adjacent to the lower wall of the housing 32, is brought into contact with the inner panel 26 and limits the rotation amount of the lower wall of the housing 32 and the door 32b. Hence, the door 32b can be stably held on the upper end of the center pillar trim 22, and the space between the center pillar trim 22 and the inner panel 26 is closed, so that the air bag tube 36 is prevented from being introduced into the space between the center pillar trim 22 and the inner panel 26.
Accordingly, when the air bag tube 36 is deployed, as shown in FIG. 3 by the phantom line, the space between the center pillar trim 22 and the inner panel 22 is closed by the guide plate 34 and the door 32b of the housing 32. Thus, the air bag 30 being deployed is not introduced into the space between the center pillar trim 22 and the inner panel 26 and is normally deployed into the passenger space of the vehicle, whereby an occupant's side portion, particularly, head portion can be effectively protected.
When the door 32b is opened as described above, the end of the head liner 24 is detached from the upper end of the center pillar trim 22 and is bent as shown in FIG. 3 by the phantom line, thereby defining an opening through which the air bag tube 36 can be deployed.
However, in this type of side air bag, since the guide plate 34 is simply formed of a plate while not being sufficiently considered in its strength, when the air bag tube 36 is deployed, the guide plate 34 is likely to be rotated with the lower wall of the housing 32 and destroyed to be touched with the inner panel 26 by the pressure of gas.
Thereupon, as the air bag tube 36 is introduced and deployed into the space between the center pillar trim 22 and the inner panel 26, a problem is caused in that it is difficult to properly protect the occupant. Also, a serious problem is caused in that, if the guide plate 34 is destroyed, it is impossible to replace the guide plate 34.
In order to cope with these problems, another guide plate for a side air bag has been disclosed in the art.
In this disclosure, the side air bag has an air bag housing in which an air bag tube is received and which has a door to be opened by the air bag tube. The air bag housing is installed an inner panel near the interface between a center pillar trim and a head liner. The guide plate has a side wall which is fastened to the inner panel by fastening means, and the lower end of the guide plate is bent to form a support member for supporting the lower surface of the air bag housing.
Due to this configuration, the guide plate can more stably guide the introduction of the air bag tube being deployed into the passenger space of the vehicle. Also, when the support member of the guide plate is destroyed, since the guide plate can be replaced with new one, repair and maintenance can be easily conducted.
Nevertheless, since the width between the head liner and the inner panel differs depending upon the kind of a vehicle and the width of the lower wall of the air bag housing differs depending upon a manufacturer of an air bag, a guide plate should be separately manufactured in conformity with the kind and the manufacture of a vehicle.